1. Department of Obstetrics and Gynecology, University of Puerto Rico School of Medicine, San Juan, PR 00936-5067, USA
2. Department of Biostatistics and Epidemiology, University of Puerto Rico School of Medicine, San Juan, PR 00936-5067, USA
3. Cancer Control and Population Sciences Program, University of Puerto Rico Comprehensive Cancer Center, San Juan, PR 00927-6346, USA